CN104046822B - A method for preparing a tantalum-based alloy with a gradient structure through solid solution strengthening - Google Patents

Abstract

The invention discloses the method that a kind of solution strengthening preparation has the tantalum-base alloy of gradient-structure, the method is: one, tantalum powder is placed in nitriding furnace, carries out cxygen nitrogen coinfiltration process to tantalum powder; Two, the tantalum powder after cxygen nitrogen coinfiltration process is placed in plasma agglomeration stove, sintering processes is carried out to the tantalum powder after cxygen nitrogen coinfiltration process, obtains tantalum-base alloy; Three, tantalum-base alloy is placed in vacuum annealing furnace, vacuum annealing process is carried out to tantalum-base alloy.Method of the present invention is first by carrying out cxygen nitrogen coinfiltration process to tantalum powder, make oxygen nitrogen in tantalum powder from top layer to core distribution gradient, then tantalum-base alloy is formed by sintering processes, the hardness of tantalum-base alloy is also from top layer to core distribution gradient, finally by vacuum annealing process, the oxygen nitrogen in tantalum-base alloy is spread gradually to core from border, can in a big way the mechanical property of controlled material, realize the intensity of tantalum-base alloy and the good combination of plasticity, extend the work-ing life of material.

Description

A method for preparing a tantalum-based alloy with a gradient structure through solid solution strengthening

technical field

The invention belongs to the technical field of preparation of high-strength tantalum alloys, and in particular relates to a method for preparing a tantalum-based alloy with a gradient structure through solid solution strengthening.

Background technique

The refractory metals tantalum and niobium are extremely versatile, but compared with their melting points, their potential strength properties are far from being discovered, and they cannot meet people's increasing application requirements. Even at low working temperature, due to its insufficient strength, it will reduce its fatigue, wear and corrosion performance, thereby shortening the service life of components. At present, tantalum or tantalum alloys are commonly used instead of gold-platinum alloys at home and abroad to make spinnerets for chemical fiber wet or dry-wet spinning, but their wear resistance is poor and they are easy to scratch, which makes it easy to work under a certain pressure for a long time. Deformation occurs, thereby increasing production costs, affecting the spinning effect of the spinneret, resulting in high defects and high yarn degradation rates. Therefore, improving the strength properties of tantalum alloys is of great significance to meet the production of special processes.

At present, the main strengthening methods of tantalum alloys are solid solution strengthening and precipitation strengthening. For example, Ta-7.5W, Ta-12W, and Ta-15W series alloys, which have been used in aerospace and missile technology for many years, rely on the solid solution strengthening of tungsten, and their strength increases with the increase of tungsten content, but the tantalum-tungsten series alloys Processing is more difficult. In addition, elements such as hafnium and carbon are added to the tantalum-tungsten alloy, and the strength performance can be further improved through the solid solution strengthening of tungsten and hafnium and the precipitation phase strengthening of hafnium carbide, but it only reaches about 800MPa. The composition of the multi-component tantalum alloy is relatively complex, and the price of the added elements such as tungsten and hafnium is relatively expensive, and the processing performance of the alloy is poor. Therefore, the development and research of low-cost high-strength tantalum alloys can not only effectively save the amount of materials used, but also expand the application range of tantalum alloys.

In general, the solid solution of oxygen and nitrogen in tantalum are harmful elements that damage the plasticity and toughness, and should be minimized during the processing and preparation of tantalum and tantalum alloys. If the solid-solution strengthening effect of nitrogen on tantalum is used, this technical problem can be well solved while retaining its plasticity to the maximum extent. However, the current research on high-oxygen-nitrogen tantalum-based alloys is basically blank.

Contents of the invention

The technical problem to be solved by the present invention is to provide a method for preparing a tantalum-based alloy with a gradient structure by solid solution strengthening in view of the above-mentioned deficiencies in the prior art. In this method, the tantalum powder is first subjected to oxygen and nitrogen co-infiltration treatment, so that the oxygen and nitrogen in the tantalum powder are distributed in a gradient from the surface layer to the core, and then the tantalum-based alloy is formed through sintering treatment. Due to the low plasma sintering temperature, oxygen and nitrogen are in it It is still distributed in a gradient, so that the hardness of the tantalum-based alloy is also distributed in a gradient from the surface to the core. Finally, the oxygen and nitrogen in the tantalum-based alloy are gradually diffused from the boundary to the core through vacuum annealing, which can control the material in a wide range. The mechanical properties of the tantalum-based alloy are well matched with the strength and plasticity, and the service life of the material is extended.

In order to solve the above-mentioned technical problems, the technical solution adopted in the present invention is: a method for preparing a tantalum-based alloy with a gradient structure through solid solution strengthening, which is characterized in that the method includes the following steps:

Step 1. Put the tantalum powder in the nitriding furnace, adjust the nitrogen flow rate of the nitriding furnace to 0.05m ³ /h～0.2m ³ /h, and carry out oxynitriding treatment on the tantalum powder under the condition of 600℃～1000℃ 5min to 90min; the mass purity of the tantalum powder is not less than 99.5%, the particle size of the tantalum powder is not less than 200 mesh, and the volume content of oxygen in the nitriding furnace is controlled to be not less than 5% during the oxynitriding process ;

Step 2. Put the tantalum powder treated by oxynitriding in step 1 in a plasma sintering furnace, adjust the pressure of the plasma sintering furnace to 200MPa~500MPa, and put the tantalum powder treated by oxynitriding in step 1 to 200MPa~500MPa. The final tantalum powder is sintered for 1 to 30 minutes to obtain a tantalum-based alloy;

Step 3. Place the tantalum-based alloy described in step 2 in a vacuum annealing furnace, adjust the vacuum degree of the vacuum annealing furnace to 10 ^-1 Pa to 10 ^-4 Pa, and vacuum the tantalum-based alloy at 700°C to 1050°C Annealing treatment 0.5h ~ 5h.

The above-mentioned method for preparing a tantalum-based alloy with a gradient structure through solid solution strengthening is characterized in that the flow rate of nitrogen gas in step 1 is 0.08m ^{3 /h to 0.12m 3 /} h, and the temperature of oxynitriding treatment is 800℃～1000℃, the time of oxynitriding treatment is 5min～30min.

The above-mentioned method for preparing a tantalum-based alloy with a gradient structure through solid solution strengthening is characterized in that the flow rate of the nitrogen gas is 0.1m ³ /h, the temperature of the oxynitriding treatment is 900°C, and the temperature of the oxynitriding treatment The time is 15 minutes.

The above-mentioned method for preparing a tantalum-based alloy with a gradient structure through solid solution strengthening is characterized in that the pressure in step 2 is 200MPa-400MPa, the temperature of the sintering treatment is 900°C-1000°C, and the time of the sintering treatment is 3min ~10min.

The above-mentioned method for preparing a tantalum-based alloy with a gradient structure through solid solution strengthening is characterized in that the pressure is 300 MPa, the sintering temperature is 950° C., and the sintering time is 5 minutes.

The above-mentioned method for preparing a tantalum-based alloy with a gradient structure through solid solution strengthening is characterized in that the degree of vacuum in step 3 is 10 ^-1 Pa to 10 ^-3 Pa, and the temperature of vacuum annealing is 800°C to 1000°C ℃, the time of vacuum annealing treatment is 0.5h～2h.

The above-mentioned method for preparing a tantalum-based alloy with a gradient structure through solid solution strengthening is characterized in that the degree of vacuum is 10 ^-2 Pa, the temperature of the vacuum annealing treatment is 900° C., and the time of the vacuum annealing treatment is 1 h.

Compared with the prior art, the present invention has the following advantages:

1. The method of the present invention firstly carries out surface oxygen nitriding treatment on the tantalum powder, so that oxygen and nitrogen are distributed in a gradient from the surface layer to the core in the tantalum powder, and then the tantalum-based alloy is formed through sintering treatment. Due to the low plasma sintering temperature , oxygen and nitrogen are still distributed in a gradient, so that the hardness of the tantalum-based alloy is also distributed in a gradient from the surface to the core. Finally, through vacuum annealing, the oxygen and nitrogen in the tantalum-based alloy gradually diffuse from the boundary to the core, which can The mechanical properties of the material can be adjusted in a wide range to achieve a good match between the strength and plasticity of the tantalum-based alloy and prolong the service life of the material.

2. In the preparation method of the present invention, the oxygen and nitrogen content is distributed in a gradient in the tantalum powder through oxygen and nitriding treatment firstly, the surface layer is strengthened by a solid solution or a compound, and the interior is a soft matrix, and then the tantalum-based alloy is prepared by plasma low-temperature sintering , due to the relatively low sintering temperature, it is difficult for oxygen and nitrogen to diffuse uniformly in the particles, and the hardness is still high in the boundary layer and low in the core in a gradient distribution, so a spatially continuous tantalum-based alloy with a combination of hard and soft is formed. The alloy has high strength and retains a certain degree of plasticity. Finally, vacuum annealing is performed on the tantalum-based alloy. Oxygen and nitrogen will gradually diffuse from the surface to the core, and the mechanical properties of the material will change accordingly. The method of the invention endows traditional materials with excellent properties, and has very broad prospects in basic research and engineering applications.

3. In the present invention, the solid solution process of oxygen and nitrogen co-infiltration is adopted, because the infiltration effect of oxygen promotes the infiltration of nitrogen atoms in tantalum, so that the solid-dissolved nitrogen and nitrides formed in the infiltration layer increase, thereby increasing the tantalum. The depth of the oxynitrided compound layer and the diffusion layer is more conducive to improving the hardness of the tantalum-based alloy material and further improving the comprehensive mechanical properties of the material.

4. The preparation method of the present invention is simple, the product is dense, stable in quality, excellent in performance, and good in repeatability. The method of the invention can not only obtain low-cost near-net shape high-strength tantalum-based alloy parts, but also provides a new idea for strengthening metals, especially refractory metals tantalum and niobium. At the same time, this method can also use cheap carbon or other elements to strengthen the surface of powder particles, which provides a reference for strengthening treatment of other metals and promotes the progress of metal material strengthening technology.

The technical solutions of the present invention will be described in further detail below with reference to the accompanying drawings and embodiments.

Description of drawings

Fig. 1 is a hardness indentation topography diagram of a tantalum-based alloy prepared in Example 1 of the present invention.

FIG. 2 is a hardness indentation image of the tantalum-based alloy prepared in Comparative Example 1.

FIG. 3 is a hardness gradient trend diagram of the tantalum-based alloy prepared in Comparative Example 1.

FIG. 4 is a hardness gradient trend graph of the tantalum-based alloy prepared in Comparative Example 2.

Fig. 5 is a hardness indentation topography diagram of the tantalum-based alloy prepared in Example 2 of the present invention.

FIG. 6 is a hardness indentation image of the tantalum-based alloy prepared in Comparative Example 3.

FIG. 7 is a hardness gradient trend graph of the tantalum-based alloy prepared in Comparative Example 3.

FIG. 8 is a hardness gradient trend graph of the tantalum-based alloy prepared in Comparative Example 4.

detailed description

Example 1

This embodiment includes the following steps:

Step 1. Place 400g of tantalum powder in a nitriding furnace, adjust the nitrogen flow rate of the nitriding furnace to 0.1m ³ /h, and carry out oxynitridation treatment on the tantalum powder at 900°C for 15 minutes; the mass of the tantalum powder The purity is not less than 99.5%, the particle size of the tantalum powder is not less than 200 mesh, and the volume content of oxygen in the nitriding furnace is controlled to be not less than 5% during the oxynitriding process;

Step 2. Put the tantalum powder treated by oxynitriding in step 1 in a plasma sintering furnace, adjust the pressure to 300MPa, and sinter the tantalum powder treated by oxynitriding at 950°C for 5 minutes to obtain Tantalum-based alloys;

Step 3. Put the tantalum-based alloy described in step 2 in a vacuum annealing furnace, adjust the vacuum degree to 10 ⁻² Pa, and vacuum anneal the tantalum-based alloy at 900° C. for 1 hour.

Fig. 1 is the hardness indentation topography diagram of the tantalum-based alloy prepared in Example 1; the test result of the mechanical properties at room temperature of the tantalum-based alloy prepared in Example 1 is: the elongation at break is 10.5%, has good plasticity, yields The strength is 1500MPa (the yield strength of the tantalum-based alloy prepared in this example is 3.95 times that of the pure tantalum powder metallurgy material).

Comparative example 1

Comparative Example 1 is the same as Example 1, except that the tantalum-based alloy in Step 2 is not subjected to vacuum annealing.

The oxygen content in the tantalum-based alloy prepared in Comparative Example 1 was 0.09%, the nitrogen content was 0.18%, and the relative density of the tantalum-based alloy was 99%.

Fig. 2 is the hardness indentation topography diagram of the tantalum-based alloy prepared in Comparative Example 1, and Fig. 3 is the hardness gradient trend diagram of the tantalum-based alloy prepared in Comparative Example 1. Combining Fig. 2 and Fig. 3, it can be seen that after oxygen-nitrogen co- The tantalum-based alloy prepared by the two-step process of infiltration treatment and sintering treatment has an obvious hardness gradient structure inside. With the increase of the distance from the surface, the microhardness of the tantalum-based alloy gradually decreases, from 7.5GPa on the surface layer to the distance from the surface. 6.0GPa at 25μm, and then down to 3.2GPa at the core.

The test results of the mechanical properties of the tantalum-based alloy prepared in Comparative Example 1 at room temperature are: the elongation at break is 18%, the yield strength is 1190 MPa, and the breaking strength is 1200 MPa.

Comparative example 2

This comparative example includes the following steps:

Step 1. Put 400g of tantalum powder in the nitriding furnace, adjust the nitrogen flow rate of the nitriding furnace to 0.3m ³ /h, pass nitrogen gas at room temperature for 1 hour to discharge the air, then raise the temperature to 900°C, and treat the tantalum in a nitrogen atmosphere. Nitriding the powder for 15 minutes; the mass purity of the tantalum powder is not less than 99.5%, and the particle size of the tantalum powder is not less than 200 mesh;

Step 2. Place the tantalum powder after nitriding treatment in step 1 in a plasma sintering furnace, adjust the pressure to 300 MPa, and sinter the tantalum powder after nitriding treatment at 950° C. for 5 minutes to obtain a tantalum-based alloy.

The nitrogen content in the tantalum-based alloy prepared in Comparative Example 2 was 0.15%.

Fig. 4 is the hardness gradient trend graph of the tantalum-based alloy prepared in Comparative Example 2. It can be seen from Fig. 4 that the tantalum-based alloy prepared by the two-step process of nitriding and sintering also has a relatively obvious hardness gradient structure inside. As the distance from the surface increases, the microhardness of the tantalum-based alloy gradually decreases, from 6.0GPa at the surface to 4.8GPa at a distance of 25μm from the surface, and then to 3.0GPa at the core. Combining Figures 3 and 4, it can be seen that the tantalum-based alloy prepared by the oxynitriding process has a more obvious hardness gradient structure and a higher overall microhardness.

The test results of the mechanical properties of the tantalum-based alloy prepared in Comparative Example 2 at room temperature are: the elongation at break is 19%, the yield strength is 1100 MPa, and the breaking strength is 1150 MPa.

Combining the nitrogen content and hardness gradient trend graphs of the tantalum-based alloys prepared in Comparative Example 1 and Comparative Example 2 above, it can be shown that the infiltration of nitrogen atoms in tantalum is promoted by the infiltration of oxygen in the process of oxynitridation treatment. , so that the nitrogen in solid solution and the nitride formed in the permeation layer increase, thereby increasing the depth of the compound layer and the diffusion layer of oxynitride in tantalum, which is more conducive to improving the hardness of the tantalum-based alloy material and further improving the comprehensive mechanics of the material performance.

Combining Figures 1 and 2, it can be seen that after vacuum annealing, the hardness gradient structure of the tantalum-based alloy still exists; combined with the room temperature mechanical properties of the tantalum-based alloys prepared in Comparative Example 1 and Comparative Example 2, the test results can be further seen It can be seen that the tantalum-based alloy material with better comprehensive mechanical properties can be prepared by using the oxygen-nitriding treatment process; combined with the comprehensive mechanical properties of the tantalum-based alloy prepared in Example 1 and Comparative Example 1, it can be seen that the vacuum annealed The tantalum-based alloy can significantly increase the hardness of the material while retaining the plasticity of the material, so that the tantalum-based alloy has better comprehensive mechanical properties.

The tantalum-based alloy prepared in this example has obvious oxygen and nitrogen content concentration gradient and hardness gradient structure inside, so that the material retains good plasticity while having high strength, and realizes the balance between the strength and plasticity of the tantalum-based alloy. Good fit.

Example 2

This embodiment includes the following steps:

Step 1. Put 400g of tantalum powder in the nitriding furnace, adjust the nitrogen flow rate of the nitriding furnace to 0.12m ³ /h, and the oxygen flow rate to 0.08m ³ /h, and carry out oxynitridation on the tantalum powder at 800°C Treat for 30 minutes; the mass purity of the tantalum powder is not less than 99.5%, the particle size of the tantalum powder is not less than 200 mesh, and the volume content of oxygen in the nitriding furnace is controlled to be not less than 5% during the oxynitriding process;

Step 2. Put the tantalum powder treated by oxynitriding in step 1 in a plasma sintering furnace, adjust the pressure to 200MPa, and sinter the tantalum powder treated by oxynitriding at 1000°C for 3 minutes to obtain Tantalum-based alloys;

Step 3. Put the tantalum-based alloy described in step 2 in a vacuum annealing furnace, adjust the vacuum degree to 10 ⁻¹ Pa, and vacuum anneal the tantalum-based alloy at 800° C. for 2 hours.

Figure 5 is the hardness indentation topography of the tantalum-based alloy prepared in Example 2. The room temperature mechanical properties test results of the tantalum-based alloy prepared in Example 2 are: the elongation at break is 15%, and it has good plasticity and yield The strength is 1250MPa (the yield strength of the tantalum-based alloy prepared in this example is 3.29 times that of the pure tantalum powder metallurgy material).

Comparative example 3

Comparative Example 3 is the same as Example 2, except that the tantalum-based alloy in Step 2 is not subjected to vacuum annealing.

The oxygen content in the tantalum-based alloy prepared in Comparative Example 3 was 0.06%, the nitrogen content was 0.08%, and the relative density of the tantalum-based alloy was 99%.

Fig. 6 is the hardness indentation topography diagram of the tantalum-based alloy prepared in comparative example 3, and Fig. 7 is the hardness gradient trend diagram of the tantalum-based alloy prepared in comparative example 3. Combining Fig. 6 and Fig. 7, it can be seen that after oxygen-nitrogen co- The tantalum-based alloy prepared by the two-step process of infiltration treatment and sintering treatment has an obvious hardness gradient structure inside. As the distance from the surface increases, the microhardness of the tantalum-based alloy gradually decreases, from 4.1GPa on the surface to the distance from the surface. 3.6GPa at 25μm, and then down to 2.9GPa at the core.

The test results of the mechanical properties of the tantalum-based alloy prepared in Comparative Example 3 at room temperature are: the elongation at break is 22%, the yield strength is 1080 MPa, and the breaking strength is 1120 MPa.

Comparative example 4

This comparative example includes the following steps:

Step 1. Put 400g of tantalum powder in the nitriding furnace, adjust the nitrogen flow rate of the nitriding furnace to 0.3m ³ /h, pass nitrogen gas at room temperature for 1 hour to discharge the air, then raise the temperature to 800°C, and treat the tantalum in a nitrogen atmosphere. Nitriding the powder for 30 minutes; the mass purity of the tantalum powder is not less than 99.5%, and the particle size of the tantalum powder is not less than 200 mesh;

Step 2. Place the tantalum powder after nitriding treatment in step 1 in a plasma sintering furnace, adjust the pressure to 200 MPa, and sinter the tantalum powder after nitriding treatment at 1000° C. for 3 minutes to obtain a tantalum-based alloy.

The nitrogen content in the tantalum-based alloy prepared in Comparative Example 4 was 0.07%.

Fig. 8 is the hardness gradient trend graph of the tantalum-based alloy prepared in Comparative Example 4. It can be seen from Fig. 8 that the tantalum-based alloy prepared by the two-step process of nitriding and sintering also has a relatively obvious hardness gradient structure inside. As the distance from the surface increases, the microhardness of the tantalum-based alloy gradually decreases, from 3.6GPa at the surface to 3.2GPa at a distance of 25μm from the surface, and then to 2.8GPa at the core. Combining Figures 7 and 8, it can be seen that the tantalum-based alloy prepared by the oxynitriding process has a more obvious hardness gradient structure and a higher overall microhardness.

The test results of the mechanical properties of the tantalum-based alloy prepared in Comparative Example 4 at room temperature are: the elongation at break is 23%, the yield strength is 980 MPa, and the breaking strength is 1010 MPa.

Combining the nitrogen content and hardness gradient trend graphs of the tantalum-based alloys prepared in Comparative Example 3 and Comparative Example 4 above, it can be explained that the infiltration of nitrogen atoms in tantalum is promoted by the infiltration of oxygen in the process of oxynitridation treatment. , so that the nitrogen in solid solution and the nitride formed in the permeation layer increase, thereby increasing the depth of the compound layer and the diffusion layer of oxynitride in tantalum, which is more conducive to improving the hardness of the tantalum-based alloy material and further improving the comprehensive mechanics of the material performance.

Combining Figures 5 and 6, it can be seen that after vacuum annealing, the hardness gradient structure of the tantalum-based alloy still exists; combined with the test results of the room temperature mechanical properties of the tantalum-based alloys prepared in Comparative Example 3 and Comparative Example 4, it can be further seen It can be seen that the tantalum-based alloy material with better comprehensive mechanical properties can be prepared by using the oxygen-nitriding treatment process; combined with the comprehensive mechanical properties of the tantalum-based alloy prepared in Example 2 and Comparative Example 3, it can be seen that the vacuum annealed The tantalum-based alloy can significantly increase the hardness of the material while retaining the plasticity of the material, so that the tantalum-based alloy has better comprehensive mechanical properties.

The tantalum-based alloy prepared in this example has obvious oxygen and nitrogen content concentration gradient and hardness gradient structure inside, so that the material retains good plasticity while having high strength, and realizes the balance between the strength and plasticity of the tantalum-based alloy. Good fit.

Example 3

Step 1. Put 400g of tantalum powder in a nitriding furnace, adjust the nitrogen flow rate of the nitriding furnace to 0.08m ³ /h, and carry out oxynitriding treatment on the tantalum powder at 1000°C for 5 minutes; the mass of the tantalum powder The purity is not less than 99.5%, the particle size of the tantalum powder is not less than 200 mesh, and the volume content of oxygen in the nitriding furnace is controlled to be not less than 5% during the oxynitriding process;

Step 2. Put the tantalum powder treated by oxynitriding in step 1 in a plasma sintering furnace, adjust the pressure to 400MPa, and sinter the tantalum powder treated by oxynitriding at 900°C for 10 minutes to obtain Tantalum-based alloys;

Step 3. Put the tantalum-based alloy described in step 2 in a vacuum annealing furnace, adjust the vacuum degree to 10 ⁻³ Pa, and vacuum anneal the tantalum-based alloy at 1000° C. for 0.5 h.

As the distance from the surface of the tantalum-based alloy prepared in this example increases, the microhardness of the tantalum-based alloy gradually decreases, and there is an obvious hardness gradient. The results of measuring the mechanical properties of the tantalum-based alloy at room temperature are: the elongation is about 13%, and the yield strength is 1310MPa, indicating that the tantalum-based alloy retains good plasticity while increasing the hardness.

The tantalum-based alloy prepared in this example has obvious oxygen and nitrogen content concentration gradient and hardness gradient structure inside, so that the material retains good plasticity while having high strength, and realizes the balance between the strength and plasticity of the tantalum-based alloy. Good fit.

Example 4

Step 1. Put 400g of tantalum powder in the nitriding furnace, adjust the nitrogen flow rate of the nitriding furnace to 0.2m ³ /h, and the oxygen flow rate to 0.15m ³ /h, and carry out oxynitridation of the tantalum powder at 600°C Treat for 90 minutes; the mass purity of the tantalum powder is not less than 99.5%, the particle size of the tantalum powder is not less than 200 mesh, and the volume content of oxygen in the nitriding furnace is controlled to be not less than 5% during the oxynitriding process;

Step 2. Put the tantalum powder treated by oxynitriding in step 1 in a plasma sintering furnace, adjust the pressure to 500MPa, and sinter the tantalum powder treated by oxynitriding at 1100°C for 1 min to obtain Tantalum-based alloys;

Step 3. Put the tantalum-based alloy described in step 2 in a vacuum annealing furnace, adjust the vacuum degree to 10 ⁻⁴ Pa, and vacuum anneal the tantalum-based alloy at 700° C. for 5 hours.

As the distance from the surface of the tantalum-based alloy prepared in this example increases, the microhardness of the tantalum-based alloy gradually decreases, and there is an obvious hardness gradient. The results of measuring the mechanical properties of the tantalum-based alloy at room temperature are: the elongation is about 14%, and the yield strength is 1260MPa, indicating that the tantalum-based alloy retains good plasticity while increasing the hardness.

The tantalum-based alloy prepared in this example has obvious oxygen and nitrogen content concentration gradient and hardness gradient structure inside, so that the material retains good plasticity while having high strength, and realizes the balance between the strength and plasticity of the tantalum-based alloy. Good fit.

Example 5

Step 1. Place 400g of tantalum powder in a nitriding furnace, adjust the nitrogen flow rate of the nitriding furnace to 0.05m ³ /h, and carry out oxynitridation treatment on the tantalum powder at 900°C for 10 minutes; the mass of the tantalum powder The purity is not less than 99.5%, the particle size of the tantalum powder is not less than 200 mesh, and the volume content of oxygen in the nitriding furnace is controlled to be not less than 5% during the oxynitriding process;

Step 2. Put the tantalum powder treated by oxynitriding in step 1 in a plasma sintering furnace, adjust the pressure to 250MPa, and sinter the tantalum powder treated by oxynitriding at 800°C for 30 minutes to obtain Tantalum-based alloys;

Step 3. Put the tantalum-based alloy described in step 2 in a vacuum annealing furnace, adjust the vacuum degree to 10 ⁻² Pa, and vacuum anneal the tantalum-based alloy at 1050° C. for 0.5 h.

As the distance from the surface of the tantalum-based alloy prepared in this example increases, the microhardness of the tantalum-based alloy gradually decreases, and there is an obvious hardness gradient. The results of measuring the mechanical properties of the tantalum-based alloy at room temperature are: the elongation is about 13.5%, and the yield strength is 1300MPa, indicating that the tantalum-based alloy retains good plasticity while increasing the hardness.

The tantalum-based alloy prepared in this example has obvious oxygen and nitrogen content concentration gradient and hardness gradient structure inside, so that the material retains good plasticity while having high strength, and realizes the balance between the strength and plasticity of the tantalum-based alloy. Good fit.

Example 6

Step 1. Place 400g of tantalum powder in a nitriding furnace, adjust the nitrogen flow rate of the nitriding furnace to 0.12m ³ /h, and carry out oxynitriding treatment on the tantalum powder at 800°C for 40 minutes; the mass of the tantalum powder The purity is not less than 99.5%, the particle size of the tantalum powder is not less than 200 mesh, and the volume content of oxygen in the nitriding furnace is controlled to be not less than 5% during the oxynitriding process;

Step 2. Place the tantalum powder after oxynitriding treatment in step 1 in a plasma sintering furnace, adjust the pressure to 350MPa, and sinter the tantalum powder after oxynitriding treatment at 950°C for 16 minutes , to obtain a tantalum-based alloy;

Step 3. Put the tantalum-based alloy described in step 2 in a vacuum annealing furnace, adjust the vacuum degree to 10 ⁻² Pa, and vacuum anneal the tantalum-based alloy at 860° C. for 2.5 hours.

As the distance from the surface of the tantalum-based alloy prepared in this example increases, the microhardness of the tantalum-based alloy gradually decreases, and there is an obvious hardness gradient. The results of measuring the mechanical properties of the tantalum-based alloy at room temperature are: the elongation is about 12%, and the yield strength is 1350MPa, indicating that the tantalum-based alloy retains good plasticity while increasing the hardness.

The tantalum-based alloy prepared in this example has obvious oxygen and nitrogen content concentration gradient and hardness gradient structure inside, so that the material retains good plasticity while having high strength, and realizes the balance between the strength and plasticity of the tantalum-based alloy. Good fit.

The above are only preferred embodiments of the present invention, and do not limit the present invention in any way. All simple modifications, changes and equivalent structural changes made to the above embodiments according to the technical essence of the present invention still belong to the technical aspects of the present invention. within the scope of protection of the scheme.

Claims (7)

1. A method for preparing a tantalum-based alloy with a gradient structure through solid solution strengthening, characterized in that the method may further comprise the steps: Step 1. Put the tantalum powder in the nitriding furnace, adjust the nitrogen flow rate of the nitriding furnace to 0.05m ³ /h～0.2m ³ /h, and carry out oxynitriding treatment on the tantalum powder under the condition of 600℃～1000℃ 5min to 90min; the mass purity of the tantalum powder is not less than 99.5%, the particle size of the tantalum powder is not less than 200 mesh, and the volume content of oxygen in the nitriding furnace is controlled to be not less than 5% during the oxynitriding process ; Step 2. Put the tantalum powder treated by oxynitriding in step 1 in a plasma sintering furnace, adjust the pressure of the plasma sintering furnace to 200MPa-500MPa, and place the tantalum powder treated by oxynitriding in step 1 at 800°C-1100°C. The final tantalum powder is sintered for 1 to 30 minutes to obtain a tantalum-based alloy; Step 3. Place the tantalum-based alloy described in step 2 in a vacuum annealing furnace, adjust the vacuum degree of the vacuum annealing furnace to 10 ^-4 Pa to 10 ^-1 Pa, and vacuum the tantalum-based alloy at 700°C to 1050°C Annealing treatment 0.5h ~ 5h. 2. A method for preparing a tantalum-based alloy with a gradient structure according to claim 1, wherein the flow rate of nitrogen gas in step 1 is 0.08m ^{3 /h to 0.12m 3 /} h, oxygen The temperature of nitriding treatment is 800° C. to 1000° C., and the time of oxynitriding treatment is 5 minutes to 30 minutes. 3. A method for preparing a tantalum-based alloy with a gradient structure according to claim 2, wherein the flow rate of the nitrogen gas is 0.1 m ³ /h, and the temperature of the oxynitriding treatment is 900° C. , The time of oxynitriding treatment is 15min. 4. A method for preparing a tantalum-based alloy with a gradient structure according to claim 1, characterized in that the pressure in step 2 is 200MPa-400MPa, and the sintering temperature is 900°C-1000°C , the time of sintering treatment is 3min～10min. 5. A method for preparing a tantalum-based alloy with a gradient structure according to claim 4, wherein the pressure is 300 MPa, the sintering temperature is 950° C., and the sintering time is 5 minutes. 6. A method for preparing a tantalum-based alloy with a gradient structure according to claim 1, wherein the degree of vacuum in step 3 is 10 ^-3 Pa to 10 ^-1 Pa, and the vacuum annealing treatment The temperature is 800°C to 1000°C, and the time for vacuum annealing is 0.5h to 2h. 7. A method for preparing a tantalum-based alloy with a gradient structure according to claim 6, wherein the degree of vacuum is 10 ^-2 Pa, the temperature of the vacuum annealing treatment is 900°C, and the vacuum annealing The processing time is 1h.